Housing and marker point holder for a marking machine



April 1969 D. OEHLERKING 3,440,861

HOUSING AND MARKER POINT HOLDER FOR A MARKING MACHINE Filed Sept. 26, 1966 "'1 n up (QI United States Patent 3,440,861 HOUSING AND MARKER POINT HOLDER FOR A MARKING MACHINE Dean Oehlerking, Sycamore, Ill., assignor to Ideal Industries, Inc., Sycamore, 111., a corporation of Delaware Filed Sept. 26, 1966, Ser. No. 581,969 Int. Cl. B21j 15/24, 13/00; B23b 45/00 US. Cl. 72-430 2 Claims ABSTRACT OF THE DISCLOSURE This invention is in the field of reciprocating markers and is concerned with a housing having bearings integrally molded therein and a marker point holder for use In such marking machine.

A primary object of my invention is a marker point holder into which a marker point can be inserted but not removed by hand.

Another object is a two-part molded marking machine housing with marker point holder bearings integrally molded into one-half thereof.

Another object is a marking machine housing which may be economically produced in high production.

Another object is a marker point holder which facilitates insertion and removal of a marker point.

Another object is a marker point holder which may be produced economically in high production.

Another object is a marking machine housing which may be molded.

Another object is a marker point holder which may be molded.

Another object is a marking machine housing and marker point holder which are greatly simplified and substantially less expensive to manufacture.

Other objects will appear from time to time in the ensuing specification and drawings in which:

FIGURE 1 is a plan view of a reciprocating marker containing my new invention;

FIGURE 2 is a partial cross-sectional view on an enlarged scale taken along line 2-2 of FIGURE 1;

FIGURE 3 is an end view of the marker point holder of FIGURE 2;

FIGURE 4 is a cross-sectional view taken along line 44 of FIGURE 2; and

FIGURE 5 is a cross-sectional view taken along line 55 of FIGURE 2.

In FIGURES 1 and 2, the reciprocating marker has been shown consisting of a two part molded housing and 12 which contains and supports a push type electrical driver 14; an on-otf switch 16; an adjusting mechanism, not shown, for regulating the marking stroke, a drive shaft 18 which engages the push-type electrical driver 14 on one end and the marker point holder 20 on the other end; a return spring 22', and a marker point holder 20 containing a marker point 44.

One part of the molded housing 10 contains two integrally molded bearings 24 and 26 having bearing surfaces 28 and 30 respectively.

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The marker point holder 20 is a semi-solid cylindrical shaft with an enlarged split collet end 32 containing four splits 36 which have been cut parallel to and through the center line of the marker point holder as shown in FIG- URE 3. The marker point holder 20 contains a hole 50 which emanates from the split collet end 32 and runs along the center line of such marker point holder wvith such hole acting as the receptacle for the marker point 44.'The marker point holder is provided with two circumferential grooves 33 and 38 into which a spring retaining ring 34 and a spring ring 40 are respectively inserted.

The marker point holder is inserted into the marker housing through bearing ports 30 and 28 which maintain the vertical alignment of the marker point 20. The marker point holder is movably retained within the marker housing 10 by a return coil spring 22. The return coil spring 22 has an inside diameter larger than the outside diameter of the marker point holder 20 so that such point holder may be inserted within such spring. At one end the return spring abuts the lower marker point holder bearing top surface 42 while the other end abuts the spring retaining ring 34.

A solid cylindrical metal marker point 44 having a pointed end 46 is inserted into the marker point holder hole 50.

The use, operation and function of this invention are as follows:

In a reciprocating marker, a marker point is rapidly reciprocated up and down such that when the marker point is placed against the surface to be marked, the marker point pits or indents and thereby marks such surface. The reciprocating movement of the marker point is generated by a push-type electrical driver which pushes I such marker point down with the downward movement being transmitted from the electrical driver through a drive shaft 18 and marker point holder 20 to the marker point 44. As the marker point holder 20 is forced in the downward direction by the drive shaft 18, the return coil spring 22 is compressed by the retaining ring 34 which is attached to such marker point holder. At the completion of the downward stroke of the electrical driver 14 and when the electrical driver is no longer exerting a downward force, the compressed return spring 22 exerts an upward force on the retaining ring thereby returning the marker point holder and drive shaft to their initial position. Such downward force of the electrical driver 14 v and upward force of the return spring 22 imparts a reciprocating up-down movement to the marker point holder 44. During such reciprocating motion, the marker point holder is retained and slides within the upper and lower marker point holder bearings 24 and 26.

A hole 50 is provided in the protruding split collet end 32 of the marker point holder 20 with such hole being located on the center line of the marker point holder and having a diameter equal to the marker point outside diameter plus several thousandths. The extending split collet end of the marker point holder is split at four equally spaced places as at 36 with such splits running along and through the center line of the marker point holder. A circumferential groove 38 is provided at the split collet end of the marker point holder with such groove containing a spring ring 40. When the spring ring 40 is installed in the marker point holder spring ring groove 38, the four tabs 52, 54, 56 and 58 created by the four splits 36 are squeezed together such that the opening 60 is closed to a smaller diameter than that of the original hole 50. When the marker point is inserted into the opening '60 and hole 50, the four tabs 52, 54, 56, and 58 and the spring ring 40 are forced open. With the marker point fully inserted into the marker point holder 20, the spring ring 40 forces the tabs 52, 54, 56, and 58 tightly against the marker point 44 and thereby retains such marker point within the marker point holder 20.

When inserting the marker point 44 into the marker point holder, a force sufiicient to overcome the dynamic friction created by the marker point outside surface sliding through the restricted opening 60 must be exerted. To remove the marker point 44 from the marker point holder 20 a force must be exerted which exceeds the static friction created by the inside surfaces of the tabs 52, 54, 56, and 58 pressing against the outside surface of the marker point. Since dynamic friction is inherently less than static friction, less force is required to insert the marker point into the marker point holder than is required to remove such marker point. A spring ring 40 is selected so that the marker point 44 may be inserted by hand into the marker point holder 20 but cannot be removed from such holder without the use of a tool such as pliers. Alhough I have shown the marker point holder having four splits 36 and four tabs 52, 54, 56, and 58, it should be understood that more or less than four such splits and tabs could be used.

The molded marker housing consists of two parts and 12. The upper marker point holder bearing 24 and lower marker point holder bearing 26, which retain and in which the marker point holder slides during its reciproeating movement, are integrally molded in one part 10 of the molded housing. By integrally molding both bearings 24 and 26 in one side of the molded housing 10, accurate alignment between the bearing surfaces 30 and 28 may be maintained. Consequently, binding of the marker point holder within such bearing surfaces 28 and 30 which would interfere with the proper reciprocating movement of such point holder is eliminated.

To facilitate free reciprocating action of the marker point holder within the bearing surfaces 28 and 30, it has been found desirable to lubricate such bearings by applying grease to the marker point holder 20 in the areas which slide within the bearings 24 and 26.

The housing parts 10 and 12 may be molded using a suitable plastic. The marker point holder 20 may be fabricated using a suitable plastic such as Cycolac.

Although I have depicted the marker point 44 as having a conical pointed end 46, it should be understood that a marker point having any end configuration suitable for marking could be used.

While it has been stated herein that the invention is particularly applicable to a reciprocating marker, it should be understood that the invention may be used in any device which must hold an insertable and removable bit while imparting a reciprocating or vibratory updown motion thereto.

While the preferred form and variation of the invention have been described, it should be understood that suitable other additions, alterations, and variations may be made without departing from the invcntions fundamental theme.

I claim:

1. In a reciprocating marker of the type including a housing containing and supporting an electrically actuated driver which together with other means imparts a reciprocating up-down motion to a marker point removably inserted into a marker point holder, the improvement comprising: a two-part molded housing with one such part having two bearings integrally molded therein in which said marker point holder slides during its reciproeating motion and said marker point holder having a split collet end containing a groove into which a spring ring is placed with such split collet end being the end into which said marker point is removably inserted and thereby retained.

2. The structure of claim 1 further characterized in that the housing containing the integrally molded bearings and the marker point holder are made from plastic.

References Cited UNITED STATES PATENTS 175,860 4/1876 Griswold 72-76 1,707,218 4/1929 Butrick 27941 2,346,474 4/1944 De la Torre 3 10-17 3,152,272 10/1964 Hovhanesian 310 CHARLES W. LANHAM, Primary Examiner. G. P. CROSBY, Assistant Examiner.

US. Cl. X.R. 30-366; 72-462; 173-470 

